Aaron Hunt was a senior at McHenry West High School in Wonder Lake, Ill. After inhaling propane fumes, he went into a seizure.

“By the time paramedics arrived, Hunt's heart had stopped, and his brain had gone without oxygen for as long as 10 minutes, hospital officials said,” according to John Keilman, a reporter for the Chicago Tribune.

Aaron spent four days on life support but the brain damage was too severe; his parents had the ventilator removed and he died on April 16.

"I speak to many parents whose kids have died from this, and while they talked to their kids about (other risky behavior), they never thought their kids would do something like this," Harvey Weiss, director of the National Inhalant Prevention Coalition, told Keilman.

Aaron’s parents were also shocked. The teen had been caught smoking marijuana and attended counseling sessions and drug education classes. During counseling, he underwent drug testing and passed every time.

"Inhalants are not detectable through most drug tests," Weiss told the Tribune. And they’re also cheap and readily available, making them “one of the drugs most widely abused by teens,” Keilman writes.

Inhaling, commonly called huffing, has increased continually over the years. In March, CNN announced a national survey from the Substance Abuse and Mental Health Services Administration that found that inhalant use among 12-year-olds is more common than marijuana, hallucinogens and cocaine combined.

Meanwhile, the University of Michigan’s Monitoring the Future study, cited by the Tribune, found that 8 percent of eighth-graders and 6 percent of high school sophomores admit to using inhalants in the last year. According to Weiss, there aren’t reliable nationwide statistics for the number of deaths caused by inhalants but “he gets as many as 150 calls a year from parents who have suffered such a loss,” Keilman reports.

Even compressed air keyboard cleaners, seemingly just air, are also considered inhalants. TeensHealth explains that these cleaners contain a gas that pushes the air from the can; inhaling these cleaners is called “dusting.” TeensHealth has more information on inhalants written in teen-friendly language.

The National Institute on Drug Abuse (NIDA) explains that inhalants (except for nitrites) produce a sensation of pleasure by depressing the central nervous system. Animal studies suggest that many abused solvents and anesthetic gases have the same effects on the central nervous system as alcohol and medications like anesthetics and sedatives. Nitrites, however, “dilate and relax blood vessels rather than act as anesthetic agents.”

In addition, toluene, found in substances such as spray paint, nail polish remover and model airplane glue, activates the dopamine system in the brain. “The dopamine system has been shown to play a role in the rewarding effects of nearly all drugs of abuse,” NIDA reports.

Someone who is using inhalants may exhibit the following signs: chemical odors, weight loss, slurred speech, nausea or loss of appetite, irritability, depression, mood swings, vomiting, dilated pupils, hallucinations, exhaustion, hidden empty spray cans or containers, and paint or other stains on clothing, the face or hands. NIDA, TeensHealth and TheAntiDrug Web site all list signs of inhalant use and how to get help.

In 2008, the death of a British boy highlighted the dangers posed by common household items. Daniel Hurley was believed to have died from cardiac arrhythmia caused by using too much Lynx body spray in an enclosed space. Other children have died from exposure to aerosol deodorant and muscle cream.

When the 2009-2010 school year began, parents and teachers had a new cause for concern: heroin use among teenagers. Previously available mostly in big cities, heroin has been steadily spreading to smaller towns, particularly in the areas of New England and the mid-Atlantic.